//使用折半或二分查找算法（不考虑溢出）
//在一个有序数组中查找具体的某个数字n

#include <stdio.h>
int main()
{
    int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
    int k = 7;
    
    int i = 0;
    int sz = sizeof(arr) / sizeof(arr[0]);
    
    int left = 0; //最左边元素下标
    int right = sz - 1; //最右边元素下标
    while (left <= right)
    {
        int mid = (left+right) / 2; //中间元素下标，此处不考虑溢出
        //若考虑溢出，则使用下面一行代码保证不越界
        //int mid = left + (right-left) / 2;
        if (arr[mid] < k)
        {
            left = mid + 1;
        }
        else if (arr[mid] > k)
        {
            right = mid - 1;
        }
        else
        {
            printf("找到了，下标是：%d\n", mid);
            break;
        }
    }
    if (left > right)
    {
        printf("找不到\n");
    }
    return 0;
}